/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package ai.platon.pulsar.parse.tika;

import org.apache.tika.exception.TikaException;
import org.apache.tika.mime.MediaType;
import org.apache.tika.mime.MimeTypeException;
import org.apache.tika.mime.MimeTypes;
import org.apache.tika.mime.MimeTypesFactory;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.parser.Parser;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import javax.imageio.spi.ServiceRegistry;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

/**
 * Parse xml config file.
 */
public class TikaConfig {

    private final Map<String, Parser> parsers = new HashMap<String, Parser>();

    private final MimeTypes mimeTypes;

    public TikaConfig(String file) throws TikaException, IOException,
            SAXException {
        this(new File(file));
    }

    public TikaConfig(File file) throws TikaException, IOException, SAXException {
        this(getBuilder().parse(file));
    }

    public TikaConfig(URL url) throws TikaException, IOException, SAXException {
        this(getBuilder().parse(url.toString()));
    }

    public TikaConfig(InputStream stream) throws TikaException, IOException,
            SAXException {
        this(getBuilder().parse(stream));
    }

    /**
     * @see <a href="https://issues.apache.org/jira/browse/TIKA-275">TIKA-275</a>
     * @deprecated This method will be removed in Apache Tika 1.0
     */
    public TikaConfig(InputStream stream, Parser delegate) throws TikaException,
            IOException, SAXException {
        this(stream);
    }

    public TikaConfig(Document document) throws TikaException, IOException {
        this(document.getDocumentElement());
    }

    /**
     * @see <a href="https://issues.apache.org/jira/browse/TIKA-275">TIKA-275</a>
     * @deprecated This method will be removed in Apache Tika 1.0
     */
    public TikaConfig(Document document, Parser delegate) throws TikaException,
            IOException {
        this(document);
    }

    public TikaConfig(Element element) throws TikaException, IOException {
        Element mtr = getChild(element, "mimeTypeRepository");
        if (mtr != null && mtr.hasAttribute("resource")) {
            mimeTypes = MimeTypesFactory.create(mtr.getAttribute("resource"));
        } else {
            mimeTypes = MimeTypesFactory.create("tika-mimetypes.xml");
        }

        NodeList nodes = element.getElementsByTagName("parser");
        for (int i = 0; i < nodes.getLength(); i++) {
            Element node = (Element) nodes.item(i);
            String name = node.getAttribute("class");

            try {
                Class<?> parserClass = Class.forName(name);
                Object instance = parserClass.newInstance();
                if (!(instance instanceof Parser)) {
                    throw new TikaException("Configured class is not a Tika Parser: "
                            + name);
                }
                Parser parser = (Parser) instance;

                NodeList mimes = node.getElementsByTagName("mime");
                if (mimes.getLength() > 0) {
                    for (int j = 0; j < mimes.getLength(); j++) {
                        parsers.put(getText(mimes.item(j)).trim(), parser);
                    }
                } else {
                    ParseContext context = new ParseContext();
                    for (MediaType type : parser.getSupportedTypes(context)) {
                        parsers.put(type.toString(), parser);
                    }
                }
            } catch (ClassNotFoundException e) {
                throw new TikaException("Configured parser class not found: " + name, e);
            } catch (IllegalAccessException e) {
                throw new TikaException("Unable to access a parser class: " + name, e);
            } catch (InstantiationException e) {
                throw new TikaException(
                        "Unable to instantiate a parser class: " + name, e);
            }
        }
    }

    public TikaConfig() throws MimeTypeException, IOException {
        ParseContext context = new ParseContext();
        Iterator<Parser> iterator = ServiceRegistry.lookupProviders(Parser.class,
                this.getClass().getClassLoader());
        while (iterator.hasNext()) {
            Parser parser = iterator.next();
            for (MediaType type : parser.getSupportedTypes(context)) {
                parsers.put(type.toString(), parser);
            }
        }
        mimeTypes = MimeTypesFactory.create("tika-mimetypes.xml");
    }

    /**
     * @see <a href="https://issues.apache.org/jira/browse/TIKA-275">TIKA-275</a>
     * @deprecated This method will be removed in Apache Tika 1.0
     */
    public TikaConfig(Element element, Parser delegate) throws TikaException,
            IOException {
        this(element);
    }

    /**
     * Provides a default configuration (TikaConfig). Currently creates a new
     * instance each time it's called; we may be able to have it return a shared
     * instance once it is completely immutable.
     *
     * @return default configuration
     */
    public static TikaConfig getDefaultConfig() {
        try {
            return new TikaConfig();
        } catch (IOException e) {
            throw new RuntimeException("Unable to read default configuration", e);
        } catch (TikaException e) {
            throw new RuntimeException("Unable to access default configuration", e);
        }
    }

    /**
     * @see <a href="https://issues.apache.org/jira/browse/TIKA-275">TIKA-275</a>
     * @deprecated This method will be removed in Apache Tika 1.0
     */
    public static TikaConfig getDefaultConfig(Parser delegate)
            throws TikaException {
        return getDefaultConfig();
    }

    private static DocumentBuilder getBuilder() throws TikaException {
        try {
            return DocumentBuilderFactory.newInstance().newDocumentBuilder();
        } catch (ParserConfigurationException e) {
            throw new TikaException("XML parser not available", e);
        }
    }

    private static Element getChild(Element element, String name) {
        Node child = element.getFirstChild();
        while (child != null) {
            if (child.getNodeType() == Node.ELEMENT_NODE
                    && name.equals(child.getNodeName())) {
                return (Element) child;
            }
            child = child.getNextSibling();
        }
        return null;
    }

    private String getText(Node node) {
        if (node.getNodeType() == Node.TEXT_NODE) {
            return node.getNodeValue();
        } else if (node.getNodeType() == Node.ELEMENT_NODE) {
            StringBuilder builder = new StringBuilder();
            NodeList list = node.getChildNodes();
            for (int i = 0; i < list.getLength(); i++) {
                builder.append(getText(list.item(i)));
            }
            return builder.toString();
        } else {
            return "";
        }
    }

    /**
     * Returns the parser instance configured for the given MIME type. Returns
     * <code>null</code> if the given MIME type is unknown.
     *
     * @param mimeType MIME type
     * @return configured Parser instance, or <code>null</code>
     */
    public Parser getParser(String mimeType) {
        return parsers.get(mimeType);
    }

    public Map<String, Parser> getParsers() {
        return parsers;
    }

    public MimeTypes getMimeRepository() {
        return mimeTypes;
    }

}